708 EHENUS. divides into two brandies at the head of the Bata- vorum Insula. The branch which flows along the German bank keeps its name and its rapid course to the Ocean. The branch which flows on the Gallic bank is broader and less rapid: this is the Vahalis ( Wiutl), which flows into the Jlosa. {Hist. v. 23.) [BATAVopaiM Insula.] He knows only two out- lets of the Rhine, and one of them is through the Mosa. The Khine, as he calls the eastern branch, is the boundary between Gallia and Germania. East of this eastern branch he places the Frisii (^Ann. iv. 72) ; and herein he agrees with Pliny, who places them between the Middle Rhine and the Flevum. Accordingly the Rhenus of Tacitus is the Rhenus of Mela and Pliny. This third branch of the Rhine seems to be that which Tacitus calls the work of Drusus (Ami. ii. 6), and which Seutonius {Clcmdius, c. 1) mentions without saying where it was : "Drusus trans Rhenum fossas novi et immensi operis effecit, quae nunc adhuc Drusinae vocantur." Germanicus in his expedition against the northern Germans (Tac. Ann. ii. 6), or- dered his fleet to assemble at the Batavorum Insula, whence it sailed through the Fossa Drusiana, and the lakes into the Ocean and to the river Amisia (^Ems). This course was probably taken to avoid the navigation along the sea-coast of Holland. On a former occasion Germanicus had taken the same course {Ann. i. 60), and his father Drusus had done the same. Ptolemy (ii. 9. § 4), who wrote after Tacitus and Pliny, is acquainted with three outlets of the Rhine. He places first the outlet of the Jlosa in 24° 40' long., 53° 20' lat. He then comes to the Batavi and to Lugdunum, which town he places in 26° 30' long., 53° 20' lat. The western mouth of the Rhine is in 26° 45' long., 53° 20' lat. The middle mouth is in 27° long., 53° 30' lat.; and the eastern in 28° long., 54° lat. His absolute numbers are incorrect, and they may be relatively incorrect also. His western outlet is a little east of Lugdunum, and this should be the Old Rhine or Rhine Proper. The middle mouth is further east, and the eastern mouth further east still. The eastern mouth may be the Yssel, but it is difficult to say what Ptolemy's middle mouth is. Gosselin supposes that Ptolemy's western mouth may have been about Zandwoord. He further supposes that the Middle Mouth ac- cording to his measures was about the latitude of Bahkum, about 4 leagues above Zandwoord, and he adds that this mouth was not known to those writers who preceded Ptolemy, and we may con- jecture that it was little used, and was the first of the outlets that ceased to be navigable. The third mouth he supposes to correspond to the pas- sage of the Vlie. But nothing can be more vague and unsatisfactory than this explanation, founded on Ptolemy's measurements and pure conjecture. So much as this is plain. Ptolemy does not reckon the Slosa as one of the outlets of the Rhine, as the Roman writers do; and he makes three outlets be- sides the outlet of the Mosa. This country of swamps, rivers, and forests through which the Lower Rhine flowed has certainly under- gone great changes since the Roman period, owing to the floods of the Rhine and the inundations of the sea, and it is very difficult, perhaps impossible, to make the ancient descriptions agree with the modern localities. Still it was a fixed opinion that the Rhine divided into two great branches, as Caesar says, and this was the division of the Rhine from EHENUS. the Waal at Pannerden, or wherever it may have been in former times. One of the great outlets was that which we call the Maas that flows by Rotttr- dam : the other was the Rhine Proper that entered the sea near Leiden, and it was the stream from Pan- nerden to Leiden that formed the boundary between Gallia and Germania. (Servius, ad Aeneid. viii. 727.) Ptolemy places all his three outlets in Gal- lia, and it is the eastern mouth which he makes the boundary between Roman Gallia and Great Ger- mania (ii. 1 1 . § 1 ). If his eastern mouth is the Yssel, he makes this river from Amheiin to the outlet of the Yssel the eastern limit of Roman Gallia in his tim.e. This may be so, but it was not so that Pliny and Tacitus understood the boun- dary. Whatever chan'_res may have taken place in the Delta of the Rhine, D'Anville's conclusion is just, when he says that we can explain the ancient condition of the places sufficiently to make it agree with the statements of the ancient authors. The floods of the Rhine have been kept in their limits by embankments of earth which begin at Wesel, in the Prussian province of Diisseldorf, and extend along the Rhine and its branches to the sea. The Romans began these works. In the time of Nero, Pompeius Paullinus, to keep his soldiers em- ployed, finished an embankment (" agger ") on the Rhine which Drusus had begun sixty-three years before. (Tac. Ann. xiii. 53.) It has sometimes been supposed that this " agger " is the " moles " which Civilis broke down in the war which he carried on against the Romans on the Lower Rhine. (Tac. Hist. v. 19.) The consequence of throwing down this " moles " was to leave neai-ly dry the channel between the Batavorum Insula and Germania, which channel is the Proper Rhine. The effect of throwing down the " moles " was the same as if the river had been driven back (" velut abacto amne "). This could not have been effected by destroying an embankment ; but if the " moles " of Drusus was a dike which pro- jected into the river for the purpose of preventing most of the water from going down the Waal, and for maintaining the channel of the Rhine on the north side of the Batavorum Insula, we can understand why Civilis destroyed and why Drusus had con- structed it. Drusus constructed it to keep the channel full on the north side of the Batavorum Insula, and to maintain this as a frontier against the Germans ; and so we have another proof that the Rhine Proper or the Middle Rhine was the boundary between Gallia and Germania in this part, as every passage of Tacitus shows in which he speaks of it. Civilis destroyed the '• moles " to stop the Romans in their pursuit of him ; for they were on the south side of the island, and had no boats there to make a bridge with. Ukert understands it so, and he is probably right. Another great Roman work in the Delta of the Rhine was the canal of Corbulo. The Roman con- querors left durable monuments of their dominion in all the countries which they invaded, even in the watery regions of the Rhine, where they had to fight with floods, with the tempests of the ocean, and a war- like people whose home was in the marshes and forests. The Rhine was the great frontier of the Romans against the German tribes. All the cities on the west or Gallic- side, from Leiden to Basle, were either of their foundation or were strengthened and fortified by them. In the time of Tiberius eight legions guarded the frontier of the Rhine.
